doc/examples/qsv_transcode: Simplify loop

Fixes: CID1428858(2/2) Logically dead code

Sponsored-by: Sovereign Tech Fund
Reviewed-by: "Xiang, Haihao" <haihao.xiang@intel.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 82cce20934)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

doc/examples/qsv_transcode.c

@@ -334,10 +334,8 @@ static int dec_enc(AVPacket *pkt, const AVCodec *enc_codec, char *optstr)
 
 fail:
         av_frame_free(&frame);
-        if (ret < 0)
-            return ret;
     }
-    return 0;
+    return ret;
 }
 
 int main(int argc, char **argv)